Bradycardia and syncope as a presentation of cardiac allograft rejection involving the conducting system.

Post-heart transplantation bradycardic syncope and arrest could be due to preferential rejection of the conduction system. We present six heart transplant patients with this presentation, two of whom died. The autopsy of one of those patients demonstrated severe rejection of the conduction system, with only mild rejection throughout the rest of the myocardium. We postulate that aggressive therapy for rejection and pacemaker placement may result in improved survival in heart transplant recipients with this clinical presentation.